Relationship between mobility and high-k interface properties in advanced Si and SiGe nanowires

For the first time, interface properties between high-k and Si or SiGe nanowires (NWs) have been experimentally investigated by adapting charge pumping technique and low-frequency noise measurement. It is found that the interface state density (D
_it
) of circular Si NWs is ~3 times higher than that of rectangular ones with a deleterious impact on the low field mobility. The oxide trap density in SiGe NWs is otherwise ~3.5 times higher than that of Si NWs which limits the mobility enhancement for this material.